1. Field of the Invention
This invention relates to an orthosis. More specifically, it relates to a laterally applied orthosis having a flexible stiffener.
2. Description of the Related Art
Patients who have suffered strokes, spinal cord injuries, muscular disorders or neurological disorders such as cerebral palsy and multiple sclerosis, often uncontrollably contract their joints in flexion, which can causes them to lose range of motion in their joints. The affected joints are the wrist, fingers, foot, toe, ankle joints, hip, elbow, and knee. In an attempt to treat or otherwise alleviate the potential loss of range of motion, physicians and physical therapists often secure an orthosis or splint across the affected joint to prevent uncontrollable flexion of the joint by stretching the joint to a desired position. The orthosis may be moved to a series of desired positions to stretch the joint and hopefully prevent a loss of range of motion.
Many different types of orthoses have been developed. For example, U.S. Pat. No. 6,261,253 to Katzin discloses a hand orthosis that limits finger and wrist flexion with a steel stiffener that provides a static resistance to the user. The stiffener is plastically deformed into the desired position to conform to the shape of the joint and surrounding limbs. However, the stiffener is made of material that resists forces to which it is normally subjected when worn by a patient. The patient is unable to move the stiffener during contracture because the stiffener provides a static resistance to the joint. While this property is useful in many circumstances, the needs of certain patients require a different type of stiffener.
Knee and elbow orthoses for treatment of undesirable flexural contractions of those joints are known. These knee and elbow orthoses use goniometers which are adjustable to allow a certain degree of joint movement. For example, where zero degrees represents the angle of a patient's arm or leg when it is straight, the goniometer can be adjusted so that the patient can only move his or her arm or leg a predetermined number of degrees freely within the range of movement allowed by the goniometer. For some patients it is undesirable to use an orthosis that allows this type of movement, even if it is only within a certain range.
Thus, while orthoses have been used to treat or alleviate the symptoms of uncontrollable joint flexion, there is a need for a laterally applied orthosis that resists flexing but which allows some joint movement.